FORD 2013 Flex v.1 - Manual (Page 369)

WARNING: When a wheel is installed, always remove any
corrosion, dirt or foreign materials present on the mounting
surfaces of the wheel or the surface of the wheel hub, brake drum or
brake disc that contacts the wheel. Ensure that any fasteners that
attach the rotor to the hub are secured so they do not interfere with
the mounting surfaces of the wheel. Installing wheels without correct
metal-to-metal contact at the wheel mounting surfaces can cause the
wheel nuts to loosen and the wheel to come off while the vehicle is in
motion, resulting in loss of control.
Note: Inspect the wheel pilot hole (1) and
mounting surface prior to installation.
Remove any visible corrosion or loose
particles.
Wheels and Tires 369
2013 Flex (471)
Owners Guide gf, 1st Printing
USA (fus)